I think they meant watches that can show actual maps, not just a line or arrow with your route. That feature has always been reserved for the more expensive watches.
The more expensive watches (Fenix) also have long battery lives: lasting up to a month on a battery that can fit in a watch. The processors still have to sip power.
The Coros watches are less than half the price, have 22 days of battery life in smartwatch mode (in the Nomad) and render maps extremely fast. If they added solar, they could probably also last a month (the Coros Apex 4 does 24 days, also without solar).
The funniest thing is that earlier versions of the Coros even used the Garmin map format (though as many small files and not a single/small number of .img). Though they have switched to the open PMTiles format in later versions.
BTW, I had a Fenix 7x solar (before a Fenix 8 AMOLED) and it would usually 'only' last about two weeks. I think you can only reach Garmin's stated time if you disable a lot of functionality.
My Instinct 3 Solar shows 34 days remaining in the battery. I charged it sometime last week, so we're talking about upper 30s at least.
That's with running activity tracking including GPS for about an hour a day, and continuous heart rate monitoring.
At least on my device (and my body) the spo2 sensor is very finicky, requiring absolution stillness, and even at that I don't think it's accurate. So I don't use that.
I also discovered recently that simply using a custom watchface - even one built with an eye toward efficiency - lowers my battery life to about 2 weeks. The native faces enjoy privileged operations and are thus highly efficient. But custom-coded stuff apparently runs in a sandbox that has the effect of costing much more power. That's unfortunate, because my custom face used custom high-legibility fonts (derived from what's on interstate signage), making it noticeably easier on my aging eyes. The built-in fonts aren't great for this.
My Fenix 8 only gets two weeks at most with pulse ox off. Yes, it's the AMOLED version, but I have the screen off by default (which should be similar to MIP). I got similar runtimes on my 7 Pro Solar without pulse ox.
Err.. my 2yo Fenix 7 Solar definitely lasts 3-4 weeks. Not AMOLED (because.. that's why), but MiP. In summer.. it can last >month. Pulse on, GPS is generally only on in solar. Screen is never off. I can obviously make it a worse UX/last longer, but I'm not sure I see the need.. even when I'm back country.